The revelations about Flynn's Russian Federation contacts - contacts that he has failed to disclose on legally required forms, leading to his forced resignation at national security adviser just a month into the Trump term - have continued despite Flynn's apparent withdrawal from the public stage.

"Concerns about General Flynn's false statements - as well as his concealment of communications with the Russian ambassador - raised obvious security concerns that should have resulted in an immediate suspension of his clearance while an investigation of the allegations proceeded", Cummings wrote.

Asked by reporters whether the White House will suspend Kushner's security clearance or hand over the documents Democrats have requested, White House spokeswoman Lindsay Walters responded, "That's something I'll have to get back to you on". The lawmaker notes Kushner's undisclosed phone calls with Russian ambassador to the US Sergey Kislyak, and undisclosed meetings he had with Kislyak and the CEO of Vnesheconombank, a state-run Russian bank under US sanctions. Gowdy did not sign on to the request from Cummings, but was alerted beforehand that the request was being sent.

Flynn's attorney told ABC News he would not comment on the new allegations. A spokesman for Kasowitz declined comment.

Senator Sheldon Whitehouse says he believes former National Security Adviser Michael Flynn is cooperating with the FBI's Russian Federation investigation.

Kushner's lawyer, former Clinton deputy attorney general Jamie Gorelick, has said that on January 18 he filed an extensive security questionnaire known as the SF86, followed by an offer the next day to the Federal Bureau of Investigation to provide omitted details of his Russian contacts during his background check interview by agents in person, the New York Times has reported.

Investigators conducting government background checks for those applying for top-secret clearances understand that people make mistakes on their SF86 disclosures and sometimes have to submit supplemental information, but Moss said he's never heard of an interim clearance being given to anyone who had failed to disclose contacts with a foreign government.

White House Press Secretary Sean Spicer defended Flynn's security clearance in April. General Flynn was a career military officer who maintained a high-level security clearance throughout his career in the military. "So the issue is - he was issued a security clearance under the Obama administration in the spring of 2016", Spicer said. "It would be gravely concerning if Mr. Spicer, Ms. Hicks, Ms. Sanders, or President Trump were aware of Mr. Kushner's Russian contacts when they made their misleading statements".

Warner told CNN he "doubts" any Trump associates testimony would be scheduled at the Senate intelligence committee before the July 4 recess.

"We have no record of General Flynn reporting this trip or any contacts with foreign officials on his security clearance renewal application or in his interview with security clearance investigators", the Democratic legislators wrote.